L形复合材料层板热压工艺密实变形过程的数值模拟

Numerical simulation on consolidation and deformation of L-shaped composite laminate in autoclave process

基于Biot固结原理和达西定律,建立了二维树脂流动与纤维密实模型,采用有限元方法实现了L形层板热压成型过程树脂压力分布、层板变形的预测。通过对AS4炭纤维/环氧3501-6等厚层板厚度变化的模拟结果与实验数据的对比分析,证明了数学模型和有限元程序的可靠性。以阳模成型90°铺层S-2玻璃纤维/环氧648L形层板为例,对工艺过程层板厚度变化进行了分析。模拟结果表明:剪切模量对拐角以及拐角与平板过渡区域的变形影响较大;平板长度对拐角区域变形影响较明显,对平板区的变形影响较小。采用热压罐制备了90°铺层S-2玻璃纤维/环氧648阳模成型L形层板,实验数据表明,固化后层板呈现拐角区厚、平板区薄的厚度不均现象,并且平板长度对拐角区厚度变化影响较显著,这与数值预测结果具有较好的一致性。

Based on Biot principle and Darcy＇s law, a two dimensional flow/compaction model and the finite element program was developed. The laminate deformation and pressure distribution can be predicted in the L-shaped laminates. Through comparison between the numerical and experimental data for thickness reduction of AS4 carbon fiber/epoxy 3501-6 laminate, the reliability of the numerical model and finite element program was validated. The laminate thickness variation was analyzed for 90° lay-up S-2 glass fiber/epoxy 648 laminates with the convex tool. It is found that the shear modulus has a significant effect on the laminate deformation at the corner and in the transition area between the flat and the corner sections. The length of flat part has a more obvious effect on the corner part deformation while relatively small influence on the flat section. The 90° lay-up S-2 glass fiber/epoxy 648 L-shaped laminates were fabricated with the autoclave process. The experimental data show that the cured laminate thickness is uneven with thicker corner and the flat part length affects the corner part thickness variation, which is consistent with the numerical results.